An interpolation frame generation is performed to increase the number of frames per unit time by interpolating interpolation frames between frames of a moving image. Image display apparatuses (liquid crystal displays, electroluminescence displays, etc.) capable of performing an interpolation frame generation can display a moving image smoothly.
In an interpolation frame generation, if a motion vector is estimated for each pixel or block on the basis of correlation between the pixel values of corresponding pixels or blocks belonging to two consecutive frames (hereinafter referred to as input frames), an interpolation frame is generated using such motion vectors.
If an object in an image is moved between an input frame (first input frame) and an input frame (second input frame) following it, a new background region (hereinafter referred to as an “occlusion region”) occurs in the second input frame. No motion vectors can be determined for an occlusion region on the basis of correlation between pixel values because it has no corresponding region in the first input frame. It is therefore necessary to determine pixel values of each interpolation frame by determining motion vectors for an occlusion region properly.